Remote wireless sensor networks may include sensor nodes spread out over a home, office building, or factory to help with energy management, comfort enhancement, security, diagnostics, and other applications.
Battery life is a key consideration when implementing a wireless sensor network as many battery-operated sensors may be in inaccessible locations. Additionally, changing batteries in a large number of sensor nodes poses huge operational and environmental costs. Radio power of these wireless nodes is a major cause of battery drain. RF standards such as ZigBee are popular in low data rate, low power applications. ZigBee and other low power RF standards use MAC and PHY layers defined by IEEE 802.15.4. An amendment to 802.15.4, called 802.15.4e uses a duty-cycled MAC (media access control) to reduce radio power consumption. Even if the radio is duty-cycled, it still consumes a majority of the current in the application. In a wireless sensor network, one of the driving parameters in the determination of battery lifetimes is the overall energy consumption during RF transmission. Transmitting large amounts of sensor collected data drives higher RF duty cycles, increasing the energy consumption of the system and reducing the overall battery lifetime of the wireless sensor network.
Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.